Flummox
/ˈflʌməks/
Definition 1 of 1
Pro Tip 1/3Unexpected Surprise
Use 'flummox' when someone is surprised and confused, not just lacking understanding. 
The plot twist in the movie flummoxed the audience.
Pro Tip 2/3Sudden Confusion
'Flummox' implies a sudden state of confusion, often temporary. 
His strange behavior flummoxed his friends.
Pro Tip 3/3Not for Everyday
'Flummox' is less common in everyday speech; it's more colorful and vivid. 
The foreign custom flummoxed the tourists.